The Cater U.S. Pat. No. 5,284,276 issued Feb. 8, 1994, discloses a meritorious pump for lotions or the like including a tubular main piston having an outward flange and seal. A stepped cylindrical pump body telescopingly receives the piston to define a pumping chamber. The piston has a unitary tubular upward axial outlet provided with a valve seat at its lower end. Adjacent and below the valve seat the wall of the piston is apertured. An actuator spout/stem, assembled as a single fixed-together, rigid unit, extends down centrally through the tubular upward outlet and seat. The lower end of the stem is formed with a valve head inside the piston in sealing engagement with the piston wall and adapted to rise to seat on the valve seat.
There is a lost-motion space between the actuator/stem and the piston so that, upon depression of the actuator, the stem drops with respect to the piston and the valve head unseats and moves below the aperture in the piston wall before the piston starts to move down. Continuing the same downward stroke, the actuator pressurizes liquid in the pump chamber and forces it out the aperture up through the valve seat and out the actuator spout.
A spring urges the actuator/stem up on the return stroke. The stem first raises up inside the piston, again opening the lost-motion space and forcing the head to seat on the valve seat and opening the aperture in the piston wall below the head. As the head engages a shoulder on the piston, the continued upward force of the spring then raises the piston. As the piston raises, it creates a vacuum in the pumping chamber, drawing lotion up through a dip tube at the lower end of the pump body, into the piston and through the aperture into the chamber ready for the next downstroke.
Under an improvement of the Cater pump disclosed in the pending patent application Ser. No. 08/902,027 filed Jul. 29, 1997, now U.S. Pat. No. 5,839,617, issued Nov. 24, 1998 and assigned to the assignee of this application, and incorporated hereinto by reference, the above-described valve seat is replaced by a second aperture in the piston wall above the aperture described. The stem head is in the form of a peripheral bi-directional fin-type seal which moves during the exercise of the lost-motion from a first position wherein the upper aperture is covered and the lower aperture uncovered to a second position wherein the lower aperture is covered and the upper aperture uncovered.
By having both apertures at the same diameter on the wall of the piston, manufacture is simplified and leaks are less likely. The head may have a peripheral seal of a single diameter. The improved arrangement better accommodates dimensional variations and does not require such precise molding. Also, finned-type seals are flexible and are more forgiving of dimensional variations. The clogging of the valve with a vertical beveled seating surface is not a concern.
In addition, the resulting structure permits separate apertures for the pump chamber inlet and discharge flow. Having separate apertures for the opposite flows, into and out of the pumping chamber, makes simpler flow paths and improves the efficiency of the pumping action in this relatively short-stroke application.
In a preferred version the two apertures may be in the form of a single elongated window, the upper portion of which, when exposed, constitutes the discharge and the lower portion, when exposed, constitutes the inlet of the pumping chamber. In the windowed version, the fin-type seals do not encounter the transverse edges of apertures which can cause wear. These two arrangements--the two separate apertures and the elongate window--are regarded as equivalent.
In another Cater U.S. Pat. No. 5,335,830 issued Aug. 9, 1994 incorporated hereinto by reference, a pump of this genre is provided with means for locking the stem with the head in a first position covering the discharge aperture. This comprises a step up in the lost-motion slot so that when the actuator is turned, the abutment surface on the actuator engages the step, nullifying the lost-motion, and the stem thereafter does not lower with respect to the piston, and the discharge is effectively "locked" closed. The '830 patent also provides an inward tooth on the retainer and an upward shoulder near the top of the piston. When the piston is pushed down and turned by the actuator, the shoulder is engaged by the tooth and the piston and actuator is locked down as is preferred for shipment.
It is an object of the present invention to provide means to give the consumer a tactile "feel" or snap when the locks are engaged.
Another object is to provide for a type of pump as shown in Cater U.S. Pat. No. 5,335,830 means assuring that the lockdown is not released until the means for disabling the discharge valve is nullified so that when the pump actuator rises from lockdown position the pump is fully operative.